Metallurgical process



Feb. 22 1927 LMSJS? W. E. GREENAWALT METALLURGICAL PROCESS Filed March 9. 1926 Ore INVENTOB.

Patented Feb, Z2,

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WILLIAM E. GREENAWAL'J, OF EENVER, COLORADG.

METALLURG-ICAL PROCESS.

Application mea March e, 1926. vserial. No. 93,524.

'Ihe process refers more particularly to the treatment of .complex ores, especially ores containing copper and Zinc, with, or Without, other associated metals, such as lead, silver, and gold, by Wet methods, with the objects ot recovering the copper direct 'from the ore as the electrolytic metal, and the Zinc either as the electrolytic metal or by crysta lisation as zinc sulphate. V

This process may be lconsidered as an improvement, or modification, of those described in my Patents, No. 1,483,056, Feb. 5,1924; No. 1,357,495, Nov. 2, 1920; No. 1,572,115, Feb. 9, 1926, and reliers more particularly to details which have proved convenient in the extraction of copper and zinc from complex ores.

The process may be best described by referring to the accompanying drawings, in which Fig. 1 represents a flow sheet in diagrammatic plan ot the process,l and Fig. 2 a diagrammatic longitudinal section through one clectrolytic unit, in connection With a leaching tank, comprisingv a reducer, a storage tank, and an electrolyzer.

In describing the process it may be assumed'that rthe ore as it comes from the mine is given the necessary preliminary treatment, such as crushing and concentration by flotation or gravity. The ore may be treated direct Without concentration if desired, but this Will be advisable only in exceptional cases, where the ore is notl readily amenable to a preliminary treatment.

It may also be vassumed that at least a small amount of high grade Zinc concen? trat-e quite :tree rom copper and a high grade copper concentrate quite free from Zinc are obtainable from the general copperzinc concentrate from the ore. It they are not obtainable from the ore they may be provided in some other Way, as from regular copper or Zinc ores.

The process will be described more particularly in reference to the treatment of copper-zinc ore, and Where copper and zinc occu" in the resulting general concentrate. The general copperezinc concentrate is roasted with a view of making as much as possible ot the copper and zinc soluble in Water and a high percentage ot' soluble in dilute acid solution. The 'fresh roasted ore may loe-assumed to be in leaching tank No. 1, and the partly leached ore in tank No. 2. rIhek acid leach solution, usually including` some Wash Water and containing copper and Zinc as Well as some impurities, such as iron, nickel, cobalt, aluminum, and soluble salts of the alkalies and alkaline earthsj, is passed from leaching tank No. 2 to leaching` tank No. 1, Where the solution is neutralized or nearlyy neutralized, and becomes heavily charged with copper and zinc.k 'Ihis solution will be known as the rich metal solution. rIhis'rich metal solution then flows through a series of electrolytic units, each comprising an SO2 reducer, a storage tank, and an electrolyzer, Where the copper is taken out ot the copper-zinc solution in stages, While the Zinc remainsin the solution, and may be recovered after copper electrolysis. p f

The rich metal solution flows from the leaching tank No. 1 into the SO2 reducer No. 1, Where ferrie iron, formed either by the roasting of the ore or by the electrolysisof the solution is reduced to the `ferrous iron. From the reducer No, 1 the reduced, or, usuallythe partly reduced, solution flows into the storage tank No. 1, Where the ferric iron is still further reduced andthe solution clarified preparatory to electrolysis.

In the electrolysis of the copper solution or copper-zinc solution, containing iron, ferrous iron is not particularly harmful and may be beneficial. Ferrie iron in the solution in copper electrolysis is highly detrimental. In the conversion of erric iron to ferrous iron by means ot sulphur dioxide, time and temperature are important factors. rIhe reaction is not a rapid one, even under ordinarily kfavorable conditions, and to meet kthis condition, a large pool of the solution should be maintained with an excess-amount of gas in the solution. The amount of the excess is not so important as that there should be an excess continuously. 'Ihis maybe done by having a large pool of the solution in the SO2 reducer, or, as preferred in this case, a large pool of the solution in circuitrelation With the reducer, so thata continuous flow of solution, treated and charged with sulphur dioxide, may floW Jfrom the reducer to the storage tank, or pool and a stream or' solution from the storage tank, or pool, yback to the reducer. In this Way the large volume of solution may at all times be charged With tree sulphur dioxide to act as a reducing agent for the ferrie iron, and in this Way the time element may be satisfactorily prosoY the solution practically remains unaffected.V

The electrolyzed solution, containing ten ric iron, 1s returned to the reducer, and the solution is circulated in a. sort oi closed ein cuit between the copper tanks, the reduc l,

and the 'storagetanln While, at the same tiine there is, preferably, a flow in a sort of closed circuit between the reducer and the storage tank, or pool.

Should it be desirable to increase the Zinc content of the solution, a part ot the solution may be returned to the ore, and the cycle repeated until the Zinc contcntof the electrolyte or solution is built up to the desired amount.

When the solution has been suiiiciently ilnpoyerished in copperA in the electrolytic Velectrolytic unit No. 2, comprising' the reducer No. 2, the Vstorage tank No. 2, and

unit No. l, comprising the SO2 reducer lo. l, storage tank No. 1, and copper tanks llo. l, a portion of the solutiony is adrancedto Si the'fcopper tanks No. 2, Where the cycle ot 4'reduction and electrolysis is repeated, niuch the same as in electrolytic unit No. l.

llhen the solution has been sutliciently impoverished in copper in electrolytic unit No. 2, a `portion is advanced to unit llo. 3, comprising` the'SO2 reducer No. 3, the stor age tank No. 3, and the copper tanks No. 8. The portion ofthe solution advanced troni one electrolytic unit to the next and through the system is known `as the advance How.

In the electrolysis ot lcopper solutions, as described, it is evident that the deposition of the copper Vfrom each electrolytic unit must be done from the solution With the -copper content at or near that of the 'advance How from one unit to another. lili a 'rich head solution is assumed as containing say 3.0% copper', and the solution is impover is'hed in electrolytic unit No. 1 to say 2.0%, with the simultaneous regeneration of acid and ferrie iron, the deposition would necessarily have to be made from the solution containing about 2.0% copper. The solution flowing from unit No. 2 to unit No. 3 would have a copper content of about 1.2%, and the deposition of the copperI Vin unit No. 2 Would have to Vproceed en that basis. The-copper content vot the solution flowing from unit No. 3 would be, say, about l0.75%. lf all the copper Were taken out in one unit, then the deposition oi the copper would Vnecessarily have to take place `about 0.75% copper content of the solution, and such a condition would be objectiona14 e, nor is itat all likely that'a pure or regir and as this acidsolution contains ironand other impurities detrimental to Zinc crystallization or lZinc electrolysis, it becomes necessary to oXidiZe the iron in thesolution asV a preparatory step in its elimination. This is preigerably done by passing'the :acid solution from electrolyticunit 3, containing, say, 0.75% copper, through pln'ag'nr cells togdepositzmost oif the rei ing;` copper and oxidize, at the saine most oif the iron inthe solution.

lt has long been known that under certain ainL 'condi ions an oxidation eliciency approxiinatir 100% can be niade with carbon anodes in the conversion ot ferrous iron to s lerric iron; it is preferred, therefore, in stripping the solution oic copper and convert- .ingr ferrous iron tolerric iron, to first pass the solution through diaphragm cells, or tanks, having` carbon anodes.

tions tor favorable oxidation of the iron rEhe condiunder these conditions is a high ferrous iron -content oi the electrolyte, high temperature,

and agitation. ln this Way a portion yof the remaining` copper maybe deposited in the cathode compartment of the diaphragm cell the deposition of the copperand the omda-- tion ot the iron in diaphragnicel-ls with lead anodesf ln any case, the lead anodes may Vbe used partly or lentirely in stripping the solutionsgoit' copper. Vifith lead anodes, about 1.75% iron oxidized for each per cent ot copper deposited. It is preferred to remove most of the copper from the rich metal solution from the leaching' tanks in open cells, or copper tanks Without diaphrapjins, and then eloctrolyze in diaphragm cells so that the remaining` copperY being` deposited will oxidize the iron to the desired extent. ln doing this, the solution is pre erably flowed t l a louv percentage ot ferrie iron, through the ucer, Where the ferrie iron is reduced, and .en tl'uough the cathode compartment ot ve diaphragm cells., and the yinapoverished pper soluti ons after having; uassed through di a- Y rom the open cells, containir l 'he cathode compartments orp the diaphragm Y Cil iso

Ll (l cells, is passed through the anode compartments, Where the iron is oxidized to the ferric condition.

The solution as it inallyT issues from the diaphragm kcells is very low in copper and contains the iron mostly or entirely in the lerric condition, and contains Yfrom live to six per cent acid as a resultl ot the copper deposition and reduction of the ferrie iron, in the copper electrolysis. In neutralizing` this regenerated acid solution re ilti'ne from the copper deposition` preparatory to zaino crystallization Vor Zinc electrolysis to recover the Zinc, it is preferred to use a very high grade roasted Zinc concentrate, or a` crude Zinc oxide. For this purpose a relatively small amount of very high grade zinc concentrate is mad-e from the Zinc ore or from the general zinc-copper concentrate. containing' little or no copper and as small a. percentage as possible oli' soluble iron. l1 such concentrate cannot be obtained from the general ore it may be obtained from other mines.

The electrolyzed copper solution is then treated With this roasted Zinc concentrate, with the `general result that Zine goes into solution for the equivalent of free acid. and the iron is precipitated. rl`he neutral, or nearly neutral solution.Y new containing' Zinc to saturation or nearly to saturation, is purified and treated to recover the Zinc, either by crystallizationby electrolysis. or otherwise, as is Well known. The roasted zinc concentrate residue containing,` the precipitated iron and precipitated residual copper 'trom the copper solution. 'is re-roasted to make the iron insoluble and put the residue in condition to make a further recovery of the Zinc and residual copperthererproin.

Any small amount of copper in the neutraliser, solution, may be eliminated Yfrom the zinc solution bv chemical precipitation, with precipitants such as metallic zinc. or hydrogen sulphide. and this chemically precipitated copper may be re-dissolved and re-deposited as the pure elec-trolytic metal, in a relatively pure copper solution.

In the recovery ofthe zinc. either by crystallization or by electrolysis, it is desirable to have as nearly a zinc saturated solution as practical, because the purification ot the solution for Zinc recovery is exi'iensive, and better etiiciencies are possible with rich zinc solution than with lean Zinc solutions. The Zinc added to the solution in neutralizing the acid regenerated in the copper deposition is a great advantage. and the rich metal solutions from the leaching` tank may vary considerably in their metal content for zinc recovery. While still nialrine,` it practical to get a saturated or nearly saturated zinc solution after copper electrolysis.

lt the rich metal solution as lirst comme; from the leaching; tank does not contain the desired metal content, it may be enriched either by returning` the partly impoverished solution from the irst electrolytic unit to the leaching tank, or by returning` part oli' the acvance flou et solution from the last, or third, electrolytic unit.

in the treatment of complex ores containcopper and Zinc, it is usually practical to Vseparate a high `grade copperconcentrate, containing little or no zinc, from the ore or from the general copper-zinc concentrate. Where this is possible it is better to treat this high grade copperv concentrate separately than to mix the copper with the copper zin@ concentrate, and then recover the copper from the copper-Zinc solutions. lt is preferred to produce a high grade copper concentrate and recover the copper therei'rom by a separate copper electrolytic system or circuit` and use the copper solution to refine. or to re-dissolve and re-deposit the impure or the loose copper deposited in the copi-aer-Zinc electrolytic circuit.

In the production of the copper concentrate, all may be made o'l one grade, roasted, leached, and the solution electrolyzed to produce the electrolytic metal. t is preferred, however, to still further separate a relatively purer concentrate, especially if the ore-contains any of the copper as chalcocite, CuQS, trom which the copper can readiig,T be dissolved Without roasting, by the ferrie iron produced by depositing` the cop per from the solution obtained` from leaching; the roasted copper ore or concentrate. rThis step performs a double function; copper is dissolved from the C1125 concentrate While at the same time the ilerric iron is reduced to the ferrous condition. and this permits or a higher etlioiency in the copper deposition, a better deposit, and smoother operation.

The electrolytic copper circuit may conveniently comprise a leaching tank for the roasted concentrate, a reducing' tanl; containing' C1123. CnS. or Cu, or all at the saine time, and will be referred to as the Guti reducer. an S02 reducer. and the electrolytic copper tanks. The CuQS may be obtained as a high grade concentrate or by partial sinelting'. the CnS may be obtained as a precipitate in treating lean and foul copper solution vvith hydrogen sulphide, and the @u may be obtain-ed as a loose or impure deposit in the Zinc-copper circuit. It is preferred to pass the solution through the CnS reducer before passingr it through the reducer.

ln treating` the roasted copper concentrate, it is leached, and the resulting' Copper solution is electrolyzed to deposit the copper and regenerate acid and ferrie iron. The solution issuing 'from the copper tanks No. 5 and containing, say, 0.25%'ferric iron, is returned to the CuS reducer, Where the lill) Cil ferrie iron is reduced While `'an equivalent of copper goes into solution. li further reduc-tion is desired, or it it is 4desired to electrolyze in the presence of a small amount of SO2 which at tinzes is beneficial, even after previous reduction ol the erric iron, the solution may be passed through the SO2 reducer No. in 'Flowing from the CuSreducer to the copper tanks llo, A portion of the solution is returned to the leaching),` tank, Where .more copper is brought into solution, and the cycle is repeated until the copper in the roasted concentrate is sulli ciently extracted. V

lf the copper concentrate contains the copper largely associated with iron, as in Ychalcopyrite or bornite, it may be desirable to eliminate some or all of the iron before applying the copper sulphide to the CnS reducer. On account et the high grade of this copper concentrate, this can conveniently be done in an electric furnace, Where l the iron may be slagged oil and a high grade containing copper sulphide obtained. ln applying this high grade copper sulphide to the electrolyte it is preferred to subdivide it, either by granulation or as shots or shreds, and this may be done by bringing' a small stream or" the molten copper sulphide troni the electric furnace in contact With a stream ot iva-ter or a streain of compressed air. The resulting subdivided copper sulphide is transierred to the CuS reducer, Where it arts effectively in reducing the ferrie iron formed by the electrolysis. By subdiv the copper sulphide as described, a large surface area of the sulphide is exposed to the action of the solution, and there will be no serious difficulty either ofpercolation or of agitation in` applying the copper' sulphide to the solution in the CnS reducer. rllhe resulting residue lroin the Vcopper sulphide, some iron, sulphur, as well as some undissolved copper, is transferred to the copper concentrate roasting furnace,

Where the sulphur is eliminated, the iron made insoluble by oxidation, and the remaining copper oxidized so as to make it readily solu'ble in dilute acid solution.

y lf the impure copper solution of the electrolytic copper circuit does not contain too much iron and other impurities, and it it contains considerable zinc, the excess or ioul solution may be transferred to the copper- Zinc circuit, so as to lreep tlfe electrolytic copper circuit at a standard oit purity for the deposition of the copper of the desired purity. The transferred acid solution troni the copper circuit will act on the copper and zinc in leaching the copper-Zinc` ore or concentrate of the copper-zinc cirrui't, and the. copper and Zinc are recovered as already described. lt, however, thesolution rejected from Athe electrolytic copper circuit .is too impure ortoo large in amount to add sufficiently extracted 'from the ore.

' relais? to the copper-Zinc circuit, the copper is precipitated 'from the Waste foul solution, preferably with hydrogen sulphide,V and the solution run to Waste. 1

rllhe hydrogen sulphide is preferably produced by combininp` hydrogen, either'Y as such, or as steam, with the sulphur vapor from the electric furnace. The sulphur vapor is brought in contact with hydrogenv or a hydrogen containing fluid Vin an ILS generator, which may conveniently' consist of chamber containinga reducing-or a catalytic agent, such as colte, glass, pumice, and maintained at a teniperatureo't' from 40G to 500 deg). C. ln the production of hydrogen sulphide in this Way, a hydrocarbon, preferably in the formel' oil, may be used with or Without steam, and forms a convenient Way ot supplying` hydrogen or a hydrogen containing` fluid and maintaininpthe reducing atmosphere ydesired for `goed operating; conditions in the H25 generator. The l'l may be used for the purpose described, or for the precipitation'of copper, arsenic, antimony,etc., in the puriiication otthe copper-zinc solution,prepara tory to the recovery of the zinc.

ln the electrolysis ot the leach solutions it is desirable to obtain a solution heavily charged with copper and Zinc and containonly a small amount of acid. This is done by applying the solution to the fresh ore in leaching tank No. 1. After the first rich solution has been taken oil and the ore partly leached, it is desirable to still :further leach the ore or concentrate to inalie a fairly close recovery of the .metals troni the ore. rl'his is the condition which ispresumed to exist in leaching tank No. 2, and the partly leached ore or concentrate is then leached with a dilute acid solution by means of which both the copper and the zinc are fairly closely extracted from the ore. rlhe copper-zinc solution trom leaching' tank No. 2 passes to the SO2 reducer No. il, and through the storage tank No. l, Vandv then to the copper tanks No, 1l, and the cycle ot' leaching, reduction, and electrolysis ,is repeated until the copper and the zinc are ln this cycle of operation the copperis all the while being deposited, While the Zinc accumulates in the solution in the acid treatment, or in electrolytic circuit No. 4l, and when theV Zinc has accumulated inthe solution tothe desired extent, the solution is transferred 'to leaching` tankl No. l, Where it is heavily charged With zinc and then becomes the rich metal solution for the recovery'ol' the copper and the Zinc, as describet'l.- Y

is desirable to in'ecipitate the copper out ot the leach. solut n in the electrolytic copper tanks No. 3 as closely as practical. A portion .ot the solution tlouf'inp; from the copper tanks No. 3, containing 't'erric iron,

llO

reisde?" is returned to the ore to pass through another complete cycle ot' solution, reduction, and electrolysis. Another portion ot the solution issuing from the copper tanks No. 3,containing terric iron, is passed through t-he anode compartment ot a diaphragm cell to still further onidize ferrous iron to the ferrie condition. This solution, high in terric iron and low in ierrous iron,'is in excellent condition' tor the elimination oit the iron trom the solution with the roasted high grade zinc concentrate or other precip-V itation agent. tt a higher iierric iron solution is desired tor the extraction ot copper from the ore, as in copper ore containing chalcocite, than that obtained from the last open cells, or copper tanks No. 3, the high i'erric iron solution from the anode compartment ot the diaphragm cell may he used for that purpose, either Wholly or partly.

ln the deposition ot' the copperin the series ot copper depositing tanks, it is pret'erred to tirst electrolyze the solution in open or non-diaphragm cells under reduced conditions ot the iron, as in copper tanks No. l and No. 2, and then, asin unit No. S, electrolyze the copper solution in open tanks or cells to alloW the outtiowing solution to contain as much ferrie iron as practical, and then pass the solution, low in copper and relatively high in acid and ferrie iron, through 'the anode compartment of the dia.u phragm cell. It' the solution is not sutticientl f im ooverished in co a er as it issues from the last or open copper tanks No. 3, a iortion may be returned to the S0, reducer hlo. 3. In this Way the iron can be effectively and economically oxidizedpreparatory to its removal in the puriiication ot the solution tor the recovery ot the zinc or other remaining metals. The small amount of copper remaining in the electrolyzed and oxidized solution Will be largely removed with the iron, and this small remaining copper, precipitated With the iron, can be subsequently recovered by 11e-roasting the roasted zinc concentrate residue to make the precipitated iron insoluble in dilute acid, While the copper and zinc Will remain soluble or be made soluble by re-roasting.

It it is desired to eliminate excess iron in the copper solution to reuse the solution, the oxidized solution issuing trom the diaphragm cells may be treated with copper oxide or roasted high grade copper concentrate` which acts to precipitate the iron out of the solution much the same as Zinc oxide or roasted high grade Zinc concentrate. Ey roasting the copper oxide residue the precipitated iron is made insoluble and the residual copper may be leached trom the insoluble iron.

It is desirable in some instances to precipitate some ot the metals, such as silver, arsenic, and antimony out ot' the solution before electrolyzing the solution to deposit the copper. rihis may be done by treating the neutral or nearly neutral solution, preferably atten St), reduction, With some of the loosely deposited granular or sponge copper obtained in the electrodeposition ot' the copper, or otherwise, Which can be effectively used for this purpose. When the copper becomes too impure With precipitated metal t'or ei'ective f use, it is Withdrawn trom the tank, and the copper separated from the precipitate. rlhe cleaned copper is then returned to the tank for further use. The separation ot the copper and precipitate can be eltected by passing the material over a concentrating table whereby the lighter precipitate is Washed away from the heavier copper.

Copper can be deposited in hard or reguline form ot high purity from a solution high in iron. When, however, the solution contains large quantities ot zinc and possibly other impurities than iron, it is ditlicult and apparently impractical to get a re'guline and pure deposit. ln such cases it is preferred tov let the loosely deposited copper drop to the bottom of the tanks, and when enough copper has accumulated, Washing it out and transferring it to another velectrolytic circuit, No. 5, comprising a CUS,

C1125, or Cu reducer, and SO2 reducer No. 5, and the copper tanks No. 5, using a relatively pure acid solution containing salts of iron as the electrolyte. In this Way the copper may be ire-dissolved, and re-deposited as the relatively pure electrolytic metal. As the solution in circuit No. 5 becomes impure for the purpose intended, it is transferred to the regular leaching and electrolytic circuit.

lhe process has been described more par# ticularly in reference to sulphate solutions; it is evident that it is applicable to chloride solution.

claim:

l. A process ot treating copper ore comprising, leaching the ore with a dilute acid solution, electrolyzing the resulting copper solution containing salts 'of iron to deposit the copper and regenerate acid and ferrie iron in an electrolytic unit comprising a reducer, a storage tank and an electrolyzer, circulating a portion of the solution in a circuit between the reducer and the storage tank, and advancing another portion to the electrolyzer.

2. A process of treating copper ore comprising, leaching the ore With a dilute acid solution to extract the copper, electrolyzing the resulting copper solution containing salts ot iron to deposit the copper and regenerate acid and ferrie iron in an electrolytic unit comprising a reducer, a storage tank and an electrolyzer, circulating a portion of the solution in a circuit between the reducer and the` storage tank, and circulating another portion in a circuit between the storage tank, the electrolyzer and the reducer.

8. A process ot treating copper ore comprising, leaching the ore with a dilute acid solution to extract the copper, electrolyzing the resulting copper' solution containing salts ot iron to deposit the copper and regenerate acid and tei-ric iron in an electrolyticv unit comprising a reducer, a storage tank and an electrolyzer, circulating` a portion of the solution in a circuit between the reducer and the lstorage tank, circulating another portion between the store-age tank, the electrolyzer and 'theV reducer, and circulating another portion between the leaching tank and the electrolyti'c unit.

et. A process ot treat-ing copper ore com prising, l'eaehingv the ore with a dilute acid solution to extract the copper, electrolyzing the resulting copper solution containing salts of iron to deposit the copper and regenerate acid and ierric iron in an electrolytic unit comprising a reducer, a storage tank and an electrolyzer, circulating a portion ot the solution in a circuit between the reducer and the storage tank, circulating a portion of the solution between the storage tank, the olect-rolyzer and the reducer, circulating another portion between the leaching1 tank and the electrolytic unit, and advancing a portion to another clectrolytic u-nit comprising a reducer, a storage tank and an electroly-zer.

5., A process orti-eating' copper ore coinprising, leaching the ore with a dilute acid solution to extract the copper, electrolyzing the resulting copper solution containing salts ot iron to deposit the coppervand regenerate acid and 'erri'c iron in an electiolytic unit comprising a reducer, a'storage t-ank and an n electrolyzer, circulating a portion ot the solution in a. circuit between the reducerand ythe storage tank, circulating a portion ot the solution between the storage tank, the electrolyz'er andthe reducer, and advancing arportionoff the solution to another electrolytic unit comprising a reducer, 'a storage tank and an electrolyzer and repeating the cycle.

6. A Jiocess of treating co iper ore coinprisi-ng, leaching the ore with a dilute acid solution, alternately7 subjecting the resulting copper solution containing salts of iron to reduction and to electrolysis in. open or noni-diaphragm cells to deposit a portion ot the copper and regenerate acid, then when the desired portion 'of the Acopper has been removed from the solution by electrolysis in the open or non-diaphragm cells reducing the solution and passing the recucedsoluvtion through theica'thode compartment ot 'a diaphragm Vcell to deposit another portion i of Y the copper.

Y 7. A process of treating copper ore'coinprising, leaching the orewith a dilute acid solution, alternately subgecting the resulting copper solution containing salts ot iron to,

reduction and to electrolysis in open or non-V diaphragm cells to deposit a portion ot the copper and regenerate acid, then when the desired portion oit the copper has been renioved trom the solution by electrolysis in the open cells reducing` the solution and passing the reduced solution through the cathode compartment of a diaphragm cell to deposit another portion of the copper, and then passing the resulting` impoverished or depleted copper solution through the anode compartment ot' the diaphragm cell, to oxidize Ji'errous iron in the solution to the ferrie condition. v v

8. A. process oftreating copper'ore coinw prising, leaching the ore with a dilute acid solution, alternately subjecting the resulting` copper solution containing saltsv ot iron to reduction and to electrolysis in open or nondiaphragni cells to deposit a portion ot the copper and regenerate acid, then when the desired portion of the copper has beeniremoved from the solution by electrolysis in open cells reducing the solution and electrolyzing the solution in diaphragm cells with carbon anodes to deposit another portion of the copper and oxidize'terrous iron to the ferrie condition. l

9. A process ol treating copper ore comprising, leaching the ore with a dilute acid solution, alternately subjecting the resulting1 copper solution containing alts ot iron to reduction and toelectrolysis in open or noudiaphragm cells to deposit a portion oit `the copper and regenerate acid, then when the desired portion of the copper has been removed Jirom the solution by electrolysis in open cells reducing the solution and electrolyzing the solution tirst in-diaphragm cells containing carbon anodes and then in diaphragm cells containing' lea'd or other met-al anodes. i

10. A process ot treating copper ore coinprising, leaching the ore with. a dilute acid solution, alternately subjecting the resulting then passing the solution through the anodeV compartment ot a diaphragm cell to oxidize ferrous iron to terric iron.

1l. A process ot treating copper ore comcopper solution containing salts of iron to Y arisinO leachin Y the ore with a dilute acid solution, electrolyzing` the resulting copper solution containing salts ot iron to deposit copper and regenerate acid in open or nondiaphragin cells, then when the solution has been sufficiently impoverished in copper and Y regenerated in acid and ferrie iron passing the solution through the anode compartment i ot a diaphragm cell to increase the ferrie :corales iron content of the solution, and returning the solution to the ore.

l2. A process ot treating copper ore containing zinc comprising, leaching the ore with a dilute acid solution to extract the copper and the zinc, subjecting the resulting copper-zinc solution containing' salts of iron to the reducing action of sulphur dioxide and to electrolysis to deposit a. portion or the copper and regenerate acid, neutralizing the acid produced by the reduction and copper deposition with roasted zinc concen-` trate containing no copper or only a relatively small amount ot copper, then purifying the solution and treating the purified solution to recover the zinc.

13. A process of treating copper ore containing zinc comprising, leaching the ore with a dilute acid solution to extract cop-` per and zinc, alternately subjecting the resulting copper-zinc solution containing salts of iron to reduction and to electrolysis to deposit a portion ot' the copper and regenerate acid, then elec'trolyzing the solution to convert ferrous iron to ferrie iron, then applying a high grade roasted zinc concentrate to the electrolyzed and oxidized solution to neutralize the acid formed by the deposition of the copper and to enrich the solution in zinc, and then recovering the zinc from the resulting' enriched zinc solution.

14:. A process of treating copper ore containing zinc comprising, leaching the ore with a dilute acid solution to extract copper and zinc, alternately subjecting the resulting copper-zinc solution containing salts ot iron to reduction and to electrolysis to deposit a portion ot the copper and regenerate acid, then electrolyzing the solution to convert more ferrous iron to fcrric iron, treating the resulting electrolyzed and oxidized solution with a high grade oxidized zinc concentrate to neutralize the acid formed by the deposition of the copper and to precipitate copper and iron trom the solution into the zinc concentrate and to enrich the solution in zinc, recovering' he zinc from the resulting enriched zinc solution, roasting the high grade zinc concentrate residue containing` precipitated copper and iron to make the iron insoluble, and then leaching the roasted high grade zinc concentrate residue to extract the remaining zinc and the contained copper.

15. A process of treating copper orecoinprising, leaching the ore With a solvent tor the copper, alternately subjecting the resulting copper solution containing salts oli iron to the action of electrolysis in open cells and to the action of a reducing agent to deposit a portion of the copper, then subjectingV the copper solution to electrolysis in open cells to deposit another portion or the copper with the simultaneous regeneration and accumulation ot ferrie iron, and then passing the solution through the anode compartment of a diaphragm cell to still further oxidize ferrous iron to erric iron.

16. A process of treating copper ore coinprising, leaching the ore With a solvent for the copper, reducing and electrolyzing the resulting copper solution containing salts of iron in open or non-diaphragm cells to deposit a portion of the copper and regenerate cid and ferrie iron, and then passing the solution through the anode compartment of a diaphragm cell to still further oxidize ferrous iron to ferrie iron.

17 prising, leaching the ore With a solvent tor the copper, reducing the resulting copper solution containing salts oi iron and electrolyzing it in open cells to deposit a portion of the copper and regenerate acid and ferriciron, then passing the solution through the anode compartment oil a diaphragm cell to still further oxidize terrous iron to the er 1ic condition, and then returning the solution or a portion thereoic to the ore to pass through another cycle.

18. A process orf treating copper ore containing other metals comprising, leaching the ore With a solvent i'or the copper, reducing the resulting copper solution ycontaining salts ot iron with sulphur dioxide reducing the acidity of the solution, then applying iinely divided copper to the solution to precipitate some or" the metallic impurities, and then electrolyzing the copper solution to deposit the copper.

19. A process of treating copper ore containing other metals comprising, leaching the ore With a solvent tor the copper, electrolytically percipitating the copper in nonadherent or loose torni on suitable cathodes, transferring the impure non-adherent copper to another electrolytic circuit with a relativcly pure iron salt solution containing ierric iron as the electrolyte, rea-dissolving the transferred loose or non-adherent copperl in the ierric salt solution with the reduction of the Yferrie iron to the ferrous condition, and then electrolyzing the resulting copper solution to deposit the copper, as the relatively pure electrolytic metal With the simultaneous regeneration ot ferrie iron and repeating the cycle.

20. A process oi treating copper ore coinprising, leaching the ore With a solvent tor the copper, reducing the resulting copper solution containing salts oi iron and electrolyzing it in open or nondiaphragin cells to deposit a portion ot the copper and regenerate acid and ferrie iron, returning a portion oit the electrolyzed solution to the ore, and passing' another portion through the anode compartment oi' a diaphragm cell to still Jfurther oxidize ferrous iron to the ferrie condition.

2l. A process of treat-ing ores of metals A process oi treating copper ore com-y lll) comprising, leaching the ore With a solvent for the metals, electrolyzing the resulting metal solution containing metals et variable valenciestodeposit the metals andraise the valency of the variable valent metals remaining in the solutionin an electrolytic unit comprising a reducer, a. storage tank and an electrolyzer, circulating a portion ot the solution in a circuit between the reducer and the storage tank, and advancing another portion to thel electrolyzer.

22. A process ot treating ores ot metals comprising, leaching` the ore With a solvent tor the metals, electrolyzing the resulting metal solution containing metals ot variable valencies to deposit the metals and raise the valency of the variable valent metals re-Y maining in the solution lin an elect-rolytic unit comprising a reducer, a storage tank and an electrolyzer, circulating a portion of the solution in a closed circuit between the reducer and Vthe storage tank, and circulate ingfanother portion in a circuit between the storage tank, the electrolyzer and the reducer.

23. A process of treating oresy ot metals comprising, leaching the ore With a solvent for the metals, applying sulphur dioxide to the resulting metal solution in a sulphur dioxide reducer, passing the solution i'roin the reducer into a storage tank containing a pool of the solution, iioiving the solution from the pool into electrolyzers to deposit a portion of the metal, circulating a portion of the solution between the reducer and the pool, and circulating another portion between the pool, the electrolyzer and the sulphur dioxide reducer.

. 24. A process ot treating copper ore containing other metalsv comprising, leaching the ore with a solvent for the copper, neutralizing the solution, applying linely divided metallic copper to the solution to precipitate some of the undesirable metallic impurities, then electrolyzing the copper solug tion to deposit the copper, and when the finely divided copper becomes fouled with precipitated impurities Washing the precipitated impurities from t-he iinely divided copper and .again applying` the finely divided copper to the leach copper solution.

25. A process of treating copper ore comprising, leaching the ore with a solvent for the copper, elcctrolyzing the resulting copper solution containing impurities to deposit the copper, transferring the loosely de posited copper to a separate refining circuit With a relatively pure electrolyte containing salts o iron and re-dissolving and redepos-iting the copper as the relatively pure electrolytic metal, and when the solution in the refining lcircuit becomes too impure tor the deposition ot relatively pure copper in the reiining circuit transferring the impure solution 'to the regular leaching and electract the Zinc and the copper, precipitatingthe copper trom ythe resulting Zinc-copper .solution and treating the solution to recover the zinc, roasting and leaching the copperzinc concentrate to extract the copper and the Zinc, electrolyzing the resulting copper- Zinc solution containing salts of iron to deposit t-he copper and regenerate acid and ferrie iron, and transferring the precipitated copper from the zinc-copper leaching circuit to the copper-Zinc leaching andV electrolytic circuit.

27. A. process ot treating copper ore containing zinc comprising, concentrating the ore to produce a copper-zinc concentrate relatively high in copper and lou7 in vZin-c and a zinc-copper concentrate relatively high in zinc and'loiv in copper, roasting and leaching the zinc-copper concentrate to eX- tract the Zincfand the copper, precipitating the copper from the resulting zinc-copper 'solution and treating the solution tov recover tlie zine, roasting andV lea-ching the copper-zinc concentrate to extract the copper and the Zinc, electrolyzing the resulting copper-Zinc solution containing salts ot iron to deposit the copper and regenerate acid and ferrie iron, transfo rring the precipitated copper from the Zinc-copper leaching circuit to the copper-Zinc leaching and electrolytic circuit, and transferring a portion of the copper-zinc solution from the coppe-rzinc leaching and electrolytic circuitto the zinc-copper leaching circuit.

, mgl/and 28. A. process ot' treatin-g copper ore coni taining Zinc comprising, leaching the ore With an acid solution to extract the copper and Zinc, alternately subjecting the resulting,

copper-zinc solution to the action of elec trolysis and to lthe action olif a reducing agent' 'for 'ferrie iron to deposit the copper' and re'- generate `aci(l applying a high grade roasted Zinc concentrate to the electrolyzed Asolution to neutralize the acid termed by the deposition oit the copper and to enrich the solution in zinc, and then recovering the Z'nc from the enriched Zinc solution.

29.` fr process of. treating copper 'ore coinprising, leaching the ore With anV acid solution to extract the copper, electrolyzing the resulting copper solutionto obtain a portion ot the copper as the relatively pure electrolytic metal, lthen electrolyzing the solution to obtain another portion of the copper as the relatively impure metal', transferring the copper deposited as the relatively impure metal to a refining circuit separate andY distinct from the leaching and electrolytic circuit from which the impure-copper was deposited, said refining circuit having an electrolyte containing ferrie iron to re-dissolve the impure copper, and then re-depositing the re-dissolved copper as the relatively pure electrolytic metal With the simultaneous regeneration of erric iron, and then redissolving more copper from the impure copper With the ferrie iron so produced and repeating the cycle.

c 30. A rocess of treating copper ore cornprising, caching the ore with a suitable solvent to extract the copper, precipitating the copper from the resulting copper solution as an impure copper precipitate, transferring the iinpure copper precipitate to a rening circuit separate and distinct from the leaching circuit from Which the impure copper precipitate Was obtained, said 'relining circuit having an electrolyte containing ferrie iron to re-dissolve the copper of the impure precipitate, electrolytically depositing the re-dissolved copper as the relatively pure electrolytic metal With the simultaneous regeneration of ferrie iron, and then re-dissolvingvmore copper from the impure copper precipitate Withthe ferrie iron so produced and repeating the cycle. v v f VVILLIAM'E. GREENAWALT. 

